In vitro susceptibility to fosfomycin in clinical and environmental extended-spectrum beta-lactamase producing and/or ciprofloxacin-non-susceptible Escherichia coli isolates

ABSTRACT Extended-spectrum beta-lactamase producing and ciprofloxacin-non-susceptible Escherichia coli are clinical and environmental issues. We evaluated the susceptibility profile of fosfomycin in non-susceptible E. coli isolated from urine and the environment. We measured the activity of fosfomycin against 319 and 36 E. coli strains from urine and environmental isolates, respectively, collected from rivers. Fosfomycin resistance profiles were investigated using the minimal inhibitory concentration (MIC), according to the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) guidelines. Antibiotic susceptibility testing revealed that 5% and 6.6% of urine samples were non-susceptible to fosfomycin according to CLSI and EUCAST guidelines, respectively. The fosfomycin MIC50/90 was 0.5/4 mg/L. Of the 36 E. coli isolates from river water, 11.1% and 13,8% were non-susceptible to fosfomycin according to CLSI and EUCAST, respectively (range ≤0.25 ≥512 mg/L). All the isolates with MIC ≥512 mg/L for fosfomycin showed the fosA3 gene. Fosfomycin resistance was more frequent in the environment than in clinical samples.

First report of the prevalence of Shiga toxinproducing Escherichia coli in ground beef in Quindío, Colombia

Introduction. Shiga toxin-producing Escherichia coli (STEC) is a foodborne pathogen associated with clinical cases of diarrhea in humans. Its main virulence factors are the Shiga toxins (Stx1 and Stx2). Cattle are the main reservoir of STEC, and many outbreaks in humans have been related to the consumption of undercooked ground beef contaminated with this pathogen. Objective. To determine the prevalence of STEC in ground beef commercialized in all the butcher shops of a township in the department of Quindío and to characterize the virulence genes of the strains found. Materials and methods. Thirty ground beef samples were taken in three different times; stx genes and other STEC virulence factors (eae, ehxA, saa) were detected by multiplex PCR. Results. The overall prevalence of STEC was 33.33 % (10/30 positive samples). We isolated eight non-O157 (LEE-negative) strains with four different genetic profiles: stx 2 / stx 2-ehxA-saa / stx 1-stx 2-ehxA-saa / stx 1-saa. Conclusion. This is the first report on the prevalence of STEC in ground beef in a township in the department of Quindío.

Introducción. Escherichia coli productora de toxina Shiga (STEC) es un agente patógeno de origen alimentario asociado a casos clínicos de diarrea en humanos; sus principales factores de virulencia son las toxinas Shiga (Stx1 y Stx2). El principal reservorio de STEC es el ganado bovino y muchos brotes en humanos se han relacionado con el consumo de carne mal cocida contaminada con este agente patógeno. Objetivo. El objetivo de este trabajo fue determinar la prevalencia de STEC en carne molida comercializada en todas las carnicerías de un municipio del departamento del Quindío y caracterizar los genes de virulencia de las cepas encontradas. Materiales y métodos. Se tomaron 30 muestras de carne molida en tres momentos diferentes; se detectaron los genes stx y otros factores de virulencia de STEC (eae, ehxA, saa) mediante PCR Multiplex. Resultados. Los resultados mostraron una prevalencia global de STEC del 33,33 % (10/30 muestras positivas). En total se aislaron ocho cepas STEC no-O157 (LEE-negativas) con cuatro perfiles genéticos diferentes: stx 2 / stx 2-ehxA-saa / stx 1-stx 2-ehxA-saa / stx 1-saa. Conclusión. Este es el primer reporte que muestra la prevalencia de STEC en carne molida en un municipio del departamento del Quindío.

Variables epidemiológicas y clínicas en pacientes pediátricos hospitalizados por infección del tracto urinario

Fundamento la infección del tracto urinario es una de las enfermedades más frecuentes en edades pediátricas y se presenta con sintomatología no específica, en especial en los niños más pequeños, en los cuales el signo más importante es la fiebre. Objetivo caracterizar una serie de casos pediátricos hospitalizados a causa de infección del tracto urinario. Métodos se realizó un estudio descriptivo, de tipo serie de casos, en el Hospital Pediátrico de Camagüey, durante el periodo de enero a marzo de 2023. La muestra quedó conformada por 112 pacientes, una vez aplicados los criterios de selección. Fueron estudiadas las variables: grupo etario y sexo, área de salud, signos y síntomas clínicos, factores de riesgo y gérmenes aislados. El procesamiento de los datos se realizó mediante el paquete estadístico para las ciencias sociales y los resultados se expresaron en valores absolutos y porcentajes. Resultados predominó el grupo etario de menores de un año (31,2 %) y el sexo femenino (68,7 %). El Área de Salud Finlay fue la que más casos aportó (22,3 %), mientras que la fiebre resultó el síntoma preponderante (93,8 %), así como el abandono de la lactancia materna se comportó como el principal factor de riesgo (25,9 %). En el 32,1 % de los casos se aisló el germen Escherichia coli. Conclusiones la infección del tracto urinario es más frecuente en lactantes femeninas, y se constata la fiebre como síntoma principal, además de recogerse como factor de riesgo sustancial el abandono de la lactancia materna.

Foundation urinary tract infection is one of the most common diseases in children and presents with non-specific symptoms, especially in younger children, in which the most important sign is fever. Objective to characterize a series of pediatric cases hospitalized due to urinary tract infection. Methods a descriptive study, of a case series type, was carried out at the Pediatric Hospital of Camagüey, from January to March 2023. The sample was made up of 112 patients, once the selection criteria were applied. The studied variables were: age group and sex, health area, clinical signs and symptoms, risk factors and isolated germs. Data processing was carried out using the statistical package for the social sciences and the results were expressed in absolute values and percentages. Results the age group of children under one year (31.2%) and the female sex (68.7%) predominated. The Finlay Health Area was the one that contributed the most cases (22.3%), while fever was the predominant symptom (93.8%), as well as abandoning breastfeeding as the main risk factor (25.9%). In 32.1% of the cases the Escherichia coli germ was isolated. Conclusions urinary tract infection is more frequent in female infants, and fever is confirmed as the main symptom, in addition to the abandonment of breastfeeding being collected as a substantial risk factor.

Extended-Spectrum Beta-lactamase and Metallo-beta-lactamase Production among Escherichia coli and Klebsiella pneumoniae Strains from Urine of Pregnant Women in Afikpo, Ebonyi State, Nigeria

Aim: The aim of this study was to determine the occurrence of Extended-spectrum beta-lactamase (ESBL) and Metallo-beta-lactamase (MBL) among Escherichia coli and Klebsiella pneumoniae strains from pregnant women attending Mater Misericordia Hospital Afikpo, Ebonyi state, Nigeria. Study Design: This is a laboratory based prospective study carried out on pregnant women suspected of having urinary tract infection and was requested to undergo diagnosis at microbiology laboratory of the hospital. Place and Duration of Study: The study was conducted in the Department of Science Laboratory Technology, Akanu Ibiam Federal Polytechnic, Unwana, Afikpo, Ebonyi State, Nigeria from October, 2022 to January, 2023. Methodology: Clean-catch midstream urine samples were collected from 206 pregnant women suspected of having urinary tract infection and were requested to undergo medical diagnosis at microbiology laboratory of the hospital. The urine samples were processed following standard microbiological procedure. Antimicrobial susceptibility testing was determined using the disc diffusion method, while ESBL phenotypes were determine by the Double-Disc Synergy Test (DDST). Disc potentiation test was performed to check for MBL production. Results: Out of the 206 urine samples processed, 24 (11.7 %) E. coli and 12 (5.8 %) K. pneumoniae were isolated. The antimicrobial susceptibility of the isolates recorded a 100 % resistance with Amoxicillin/Clavulanic acid and Cotrimoxazole. The Gram-negative isolates showed a high sensitivity of 100 % to Netilmicin, Meropenem and Ofloxacin. Overall, 35 (97.2 %) multidrug resistance (MDR) was observed of the bacteria isolates. A total of 9 (37.5 %) E. coli and 4 (33.3 %) K. pneumoniae was found positive for ESBL production whereas, 5 (20.8 %) E. coli and 2 (16.7 %) K. pneumoniae were MBL positive. Conclusion: The level of drug resistance in this study underscores the need for regular surveillance for effective management of urinary tract infection in pregnancy.

Actividad bactericida de anticuerpos anti-ABO en colonias aisladas de Escherichia coli

Se ha estudiado la interacción entre antígenos ABO y microorganismos, incluidos los presentes en la microbiota, sobre la posible acción de antígenos y anticuerpos ABO en la susceptibilidad a enfermedades infecciosas. El objetivo de esta investigación fue determinar el título mínimo de la bacteria Escherichia coli capaz de sufrir la acción bactericida in vitro de los anticuerpos humanos anti-ABO. La selección de las muestras de sangre utilizadas se realizó mediante la aplicación de un cuestionario, fenotipado sanguíneo (un voluntario de cada fenotipo ABO) y la titulación de anticuerpos ABO. Se preparó una suspensión bacteriana (inoculo) y se agregó al suero de los voluntarios, seguido de la inoculación en Mueller Hinton Agar, luego de 24 horas, los resultados se leyeron e interpretaron con análisis por duplicado. No hubo diferencia significativa en la Prueba Bactericida entre las pruebas 1 y 2 en los grupos sanguíneos A, B, AB, O y Control Positivo. Hubo una diferencia significativa en el suero humano puro cuando se analizó el Grupo A x Control Positivo; Grupo B x Control Positivo; Grupo AB x Control Positivo y Grupo O x Control Positivo. No hubo diferencia significativa en las otras diluciones. Se concluye que los anticuerpos anti-ABO tienen efecto bactericida cuando existe una alta concentración de bacterias en el ambiente.

The interaction between ABO antigens and microorganisms, including those present in the microbiota, has been studied about the possible action of antigens and ABO antibodies in susceptibility to infectious diseases. This research aimed to determine the minimum titer of the Escherichia coli bacteria capable of undergoing in vitro bactericidal action of human anti-ABO antibodies. The selection of blood samples was performed through a questionnaire, blood phenotyping (one volunteer of each ABO phenotype), and the titration of ABO antibodies. A bacterial suspension (inoculum) was prepared and added to the serum of the volunteers, followed by inoculation in Mueller Hinton Agar. After 24 hours, the results were read and interpreted with duplicate analysis. There was no significant difference in the bactericidal test between tests 1 and 2 in blood groups A, B, AB, O, and Positive Control. There was a significant difference in pure human serum when Group A x Positive Control was analyzed, Group B x Positive Control, Group AB x Positive Control, and Group O x Positive Control. There was no significant difference in the other dilutions. It is concluded that anti-ABO antibodies have a bactericidal effect when there is a high concentration of bacteria in the environment.

Molecular Detection of Plasmid-Mediated Quinolone Resistance Genes (qnrA and aac(6?)-Ib-cr) in Drug Resistant Escherichia coli, Sudan

Background: The quinolone group, a synthetic antimicrobial, is widely used worldwide to treat many diseases, including those caused by Gram-negative bacteria. Escherichia coli and others are among the bacteria that produce quinolone resistance genes (qnr) such as qnrA and aac(6?)-Ib-cr. Objective: The present study aimed to the isolate Escherichia coli from patients attending some Hospitals in Wad Medani city, identification of drug resistance patterns and detection of the frequency of quinolones resistance genes; qnrA and aac(6?)-Ib-cr among isolated strains. Methods: A cross-sectional descriptive, hospital-based study included 119 Escherichia coli strains was conducted. A designed questionnaire used for demographic data collection and the attitude toward antimicrobials usage. Clinical specimens were processed for aerobic bacterial isolation and identification. Antimicrobial sensitivity performed by Kirby Bauer disc diffusion technique according to the CLSI guidelines. Presence of qnrA and aac(6?)-Ib-cr genes was assessed by multiplex PCR. Results: Most strains of Escherichia coli originated from urine 53.8% (64/119) and wounds 42.9% (51/119) specimens. Meropenem had the best effect against tested strains with susceptibility of 85% (101/119). Multiplex PCR assay, using specific primers, demonstrated that 41.2% (49/119) and 37.8% (45/119) of isolated Escherichia coli possessed qnrA and aac(6?)-Ib-cr genes respectively. Conclusion: The high rate of qnrA and aac (6)-Ib-cr genes among Escherichia coli necessitate the usage of molecular tools in detecting the genetic determinants of drug resistance microorganisms in countries such as Sudan.

First molecular characterization of Escherichia coli O157:H7 isolates from clinical samples in Paraguay using whole-genome sequencing Molecular characterization of Escherichia coli O157 isolates from Paraguay / Primera caracterización molecular de aislamientos de Escherichia coli O157:H7 provenientes de muestras clínicas en Paraguay utilizando secuenciación de genoma completo

Abstract Escherichia coli O157:H7 is a foodborne pathogen implicated in numerous outbreaks worldwide that has the ability to cause extra-intestinal complications in humans. The Enteropathogens Division of the Central Public Health Laboratory (CPHL) in Paraguay is working to improve the genomic characterization of Shiga toxin-producing E. coli (STEC) to enhance laboratory-based surveillance and investigation of foodborne disease outbreaks. Whole genome sequencing (WGS) is proposed worldwide to be used in the routine laboratory as a high-resolution tool that allows to have all the results in a single workflow. This study aimed to carry out for the first time, the genomic characterization by WGS of nine STEC O157:H7 strains isolated from human samples in Paraguay. We were able to identify virulence and resistance mechanisms, MLST subtype, and even establish the phylogenetic relationships between isolates. Furthermore, we detected the presence of strains belonging to hypervirulent clade 8 in most of the isolates studied.

Resumen Escherichia coli O157:H7 es un patógeno transmitido por alimentos implicado en numerosos brotes en todo el mundo y es capaz de causar complicaciones extraintestinales en humanos. La sección de «Enteropatógenos¼ del Laboratorio Central de Salud Pública trabaja en mejorar la caracterización genómica de STEC, de modo de potenciar la vigilancia laboratorial y la investigación de brotes de enfermedades transmitidas por alimentos. La secuenciación de genoma completo (WGS, por sus siglas en inglés) se propone a nivel mundial como una herramienta de alta resolución para ser utilizada en el laboratorio de rutina, ya que permite obtener todos los resultados en un único proceso. El objetivo de este trabajo fue llevar a cabo, por primera vez, la caracterización genómica por WGS de nueve cepas STEC O157:H7 aisladas en Paraguay a partir de muestras de origen humano. Pudimos identificar los factores de virulencia, los mecanismos de resistencia, el subtipo MLST, e incluso pudimos establecer la relación filogenética entre los aislamientos. Además, detectamos que la mayoría de las cepas pertenecían al clado hipervirulento 8.

Comprehensive evaluation of abattoirs with no Hazard Analysis Critical Control Point plan in Tucumán,Argentina / Evaluación integral de frigoríficos sin un plan de análisis de peligros y puntos críticos de control en Tucumán, Argentina

Abstract This work focused on the comprehensive study of two provincial transit abattoirs inTucumán, Argentina, with no Hazard Analysis Critical Control Point (HACCP) plan. Visits (n = 20)were conducted between 2016 and 2018 during the operational and post-operational processes.Risk was estimated and the bacteriological analysis of carcass and environmental samples wasperformed. Risk estimation showed the predominance of high risk in both abattoirs. The maindeviations from the HACCP plan were: deficient building conditions, deficient workflow, lack of sectorization of changing rooms and bathrooms, lack of implementation of Standardized Sanitary Operational Procedures, and no food safety training of workers. The counts of indi-cator microorganisms from both abattoirs were not significant. Salmonella spp. was isolated from 7.5% carcass and 7.3% environmental samples. The Salmonella serovars identified were Cerro, Corvallis, Havana and Agona. Shiga toxin (stx) genes were detected in 24.4% carcass and 30.9% environmental samples. The isolates were characterized as Escherichia coli O8:H7/stx1, O116:H49/stx2 and O136:H40/stx2. Based on these results, it would be possible to implement an improvement plan in Tucumán abattoirs together with the local health authorities. Still, the need to work jointly with the sanitary authority in search of a unique sanitary standard for Argentina remains unaddressed.

Resumen Este trabajo se centró en el estudio integral de dos frigoríficos de tránsito provincial en Tucumán, Argentina, carentes de un plan de análisis de peligros y puntos críticos de control (HACCP, por sus siglas en inglés). Las visitas (n = 20) se realizaron entre 2016 y 2018 durante los procesos operativos y posoperativos. Se realizó la estimación del riesgo y el análisis bacteriológico de medias reses y muestras ambientales. La estimación del riesgo demostró un predominio de riesgo alto en ambos frigoríficos. Las principales desviaciones del plan HACCP fueron las deficientes condiciones edilicias, un inadecuado flujo de trabajo, la falta de sectorización de vestuarios y banños, una implementación nula de procedimientos operativos estandarizados de saneamiento y una insuficiente capacitación en seguridad alimentaria de los operarios. Los recuentos de microorganismos indicadores de ambos frigoríficos no presentaron diferencias significativas. Salmonella spp. se aisló del 7,5% de muestras de medias reses y del 7,3% de muestras ambientales. Se identificaron las siguientes serovariedades de Salmonella: Cerro, Corvallis, Havana y Agona. Se detectaron genes de toxina Shiga (sfx) en el 24,4% de las muestras de medias reses y en el 30,9% de las muestras ambientales. Los aislamientos se caracterizaron como Escherichia coli O8:H7/sfx1, O116:H49/sfx2 y O136:H40/sfx2. Teniendo en cuenta estos resultados, sería posible implementar un plan de mejoramiento en frigoríficos de Tucumán conjuntamente con las autoridades locales de salud. Aun así, sigue sin abordarse la necesidad de trabajar en vinculación con las autoridades sanitarias en la búsqueda de una norma integrada única para Argentina.

Análisis retrospectivo de perfil microbiológico y resistencia antimicrobiana en infección urinaria pediátrica de hospitales públicos de Quito-Ecuador

Objetivo: Determinar el perfil microbiológico y resistencia antimicrobiana en infección urinaria en niños. Materiales y métodos: Estudio descriptivo, transversal, observacional y multicéntrico. Se estudiaron 445 urocultivos procesados y los resultados de antibiogramas en tres hospitales públicos de Quito (Ecuador). En relación con los agentes causales se establecieron frecuencias absolutas y proporciones. En el análisis bivariable entre el antecedente de malformación renal o de la vía urinaria y el riesgo de infección, se aplicó el test Chi2 (p < 0,05) y la RP [IC 95 %; p < 0,05]. Resultados: Se evidenció una resistencia ante aminopenicilinas del 73,5 %; ampicilina más sulbactam 31,8 %; trimetoprim-sulfametoxazol 55,5 %; cefalosporinas de primera y segunda generación hasta 33 %; cefalosporinas de tercera y cuarta generación del 21,3 al 47 %. Ante malformación urinaria y aislamiento de bacterias diferentes a Escherichia coli, se identificó a Klebsiella pneumoniae RP 2,66 [IC 95 %, 1,9-3,6; p < 0,05] y Pseudomonas aeruginosa RP 2,07 [IC 95 %, 1,2-3,5; p < 0,05]. Conclusiones: En nuestro medio, ante el diagnóstico de infección urinaria, no parece adecuado iniciar tratamiento antibiótico con aminopenicilinas, trimetoprim-sulfametoxazol ni cefalosporinas de primera a cuarta generaciones por su elevada resistencia. La presencia de malformación urinaria se asocia a infección por bacterias diferentes de Escherichia coli.

Objective: Determine the microbiological profile and antimicrobial susceptibility in urinary infection in children. Materials and methods: Descriptive, cross-sectional, observational, and multicenter study. 445 urine cultures and the results of antibiograms were studied in three public hospitals in Quito (Ecuador). In relation to the causal agents, absolute frequencies and proportions were established. In the bivariate analysis, Chi-squared test (p < 0.05) and PR [CI 95 %; p < 0.05] were applied between history of kidney or urinary tract malformation and risk of infection. Results: There was evidence of resistance to aminopenicillins of 73.5 %; ampicillin plus sulbactam 31.8 %; trimethoprim-sulfamethoxazole 55.5 %; first and second generation cephalosporins up to 33 %; resistance to third and fourth generation cephalosporins from 21.3 to 47%. In relation to urinary malformation and the isolate of a bacteria different from Escherichia coli, Klebsiella pneumoniae PR 2,66 [CI 95 %, 1.9-3.6; p < 0.05] and Pseudomonas aeruginosa PR 2.07 [CI 95 %, 1.2-3.5; p < 0.05] were identified. Conclusions: In our locality it wouldn't be appropriate to start antibiotic treatment with aminopenicillins, trimethoprim-sulfamethoxazole or first to fourth generation cephalosporins in urinary tract infection due to their resistance. The presence of urinary malformation is associated with infection by bacteria other than Escherichia coli.

Características clínicas y microbiológicas de la infección de vías urinarias bajas en población ambulatoria / Clinical and Microbiological Characteristics of Lower Urinary Tract Infections in an Outpatient Population

Introducción: El tratamiento de las infecciones del tracto urinario es casi siempre empírico, lo que genera una serie de problemas en la consulta diaria. Objetivo: Caracterizar clínica y microbiológicamente las infecciones de vías urinarias bajas no complicadas en pacientes de una clínica de primer nivel. Métodos: Se realizó un estudio transversal descriptivo. La identificación de las bacterias del cultivo de orina se efectuó por métodos establecidos. La prueba de susceptibilidad a los antimicrobianos se realizó por la técnica Kirby-Bauer. Se utilizó el programa estadístico SPSS versión 26, con la prueba de ji al cuadrado y un análisis multivariado discriminante. Se calculó también razón de momios con el programa Epi-Info. Resultados: Se incluyeron 270 pacientes, con frecuencia de 39,3 por ciento de cultivos positivos, y Escherichia coli como la especie predominante. Se identificaron, además, 31,3 por ciento de bacterias Gram positivas. Se presentó significancia estadística entre la infección urinaria y factores como el sexo, y la infección del tracto urinario previa en las mujeres. Se obtuvo 100 por ciento de cepas resistentes a ampicilina. En general, se obtuvieron porcentajes de resistencia altos en los antimicrobianos probados. Conclusiones: Escherichia coli fue la especie más frecuentemente aislada, sin embargo, existe una serie de microorganismos implicados en enfermedades del tracto genital como Gardnerella vaginalis, que parecen estar involucrados en la etiología de las infecciones del tracto urinario. Se identificaron factores de riesgo como el sexo biológico y las infecciones previas en mujeres. Se obtuvieron porcentajes de resistencia altos en los antimicrobianos probados(AU)

Introduction: The management of urinary tract infections is almost always empirical, which generates a series of problems in the daily consultation. Objective: To characterize, clinically and microbiologically, uncomplicated lower urinary tract infections in patients of a primary level clinic. Methods: A descriptive and cross-sectional study was carried out. Bacterial identification in urine culture was performed by established methods. Antimicrobial susceptibility testing was performed using the Kirby-Bauer technique. The statistical software SPSS (version 26) was used, with the chi squared test and multivariate discriminant analysis. Odds ratios were also calculated with the Epi-Info program. Results: A total of 270 patients were included, with a 39.3percent frequency of positive cultures and Escherichia coli as the predominant species. In addition, 31.3percent of Gram-positive bacteria were identified. There was statistical significance between urinary tract infection and factors such as sex or previous urinary tract infection in women. One result was 100percent of ampicillin-resistant strains. In general, high percentages of resistance were obtained for the tested antimicrobials. Conclusions: Escherichia coli was the most frequently isolated species; however, there is a number of microorganisms implicated in genital tract diseases, such as Gardnerella vaginalis, which appear to be involved in the etiology of urinary tract infections. Risk factors such as biological sex and previous infections in women were identified. High percentages of resistance were obtained for the tested antimicrobials(AU)

Characterization of third generation cephalosporin-resistant Escherichia coli clinical isolates from Ushuaia, Argentina / Caracterización de aislamientos clínicos de Escherichia coli resistente a cefalosporinas de tercera generación de Ushuaia, Argentina

Abstract Escherichia coli is one of the main human pathogens causing different hospital- and community-acquired infections. During the period from January 2013 to March 2015, 1.96% (32/1632) of E. coli isolates recovered at the Hospital Regional de Ushuaia, Tierra del Fuego province, were resistant to third-generation cephalosporins (TGCs). These isolates were resistant to cefotaxime (91%) and/or ceftazidime (28%). No resistance to carbapenems was detected. Twenty-six isolates were positive for blaCTX-M gene, grouped as CTX-M-1/15 (54%); CTX-M-9/14 (25%); CTX-M-2 (17%); and CTX-M-1/15 plus CTX-M-9/14 (4%). Five TGC-resistant strains were positive for blaCMY gene, while one strain harbored TEM-19 ESBL. Twelve isolates were identified as ST131 E. coli hyperepidemic clone, and one as ST69. Genome sequence analysis of seven blaCTX-M-15 E. coli selected isolates confirm the circulation of ST131, ST617 and ST405 international high-risk clones in the city of Ushuaia.

Resumen Escherichia coli es uno de los principales patógenos humanos causantes de diferentes infecciones de inicio hospitalario y comunitario. Se determinó que el 1,96% (32/1.632) de los aislamientos de E. coli recuperados entre enero de 2013 y marzo de 2015 en el Hospital Regional de Ushuaia, provincia de Tierra del Fuego, fueron resistentes a cefalosporinas de tercera generación (CTG). Estos aislamientos fueron resistentes a cefotaxima (91%) y/o a ceftazidima (28%). No se detectó resistencia a los carbapenemes. Veintiséis aislamientos fueron positivos para el gen blaCTX-M, agrupados como CTX-M-1/15 (54%), CTX-M-9/14 (25%), CTX-M-2 (17%) y CTX-M-1/15 más CTX-M-9/14 (4%). Cinco cepas resistentes a CTG dieron positivo para el gen blaCMY, mientras que un aislamiento presentó la BLEE TEM-19. Doce aislamientos se identificaron como clon hiperepidémico E. coli ST131 y uno como ST69. El análisis de las secuencias del genoma de siete aislamientos seleccionados de E. coli blaCTX-M-15 confirmó la circulación de los clones internacionales de alto riesgo ST131, ST617 y ST405 en la ciudad de Ushuaia.

Multiple Resistance in Clinical Isolates of Escherichia coli and Plasmid-mediated Quinolone Resistance Genes

Quinolone antibiotics have been commonly used to treat cases of multiple antibiotic resistance. Unfortunately, quinolone antibiotics have so much been resisted by infectious bacterial agents. This study aimed to evaluate the susceptibility of some clinical isolates of E. coli to some commonly used quinolone antibiotics and the determination of the plasmid-encoded quinolone resistance genes. Our results showed the plasmid quinolone-resistance genes in the following prevalence: qnr genes: qnr S (71.4 %); qnr B (15.4 %); qnr S and B (12.1 %); aac (6) lb-cr (4 %); Efflux genes: oqxA (7.7 %); oqxB (25.3 %); qepA (12.1 %); oqxA and oqxB (5.5 %). We conclude that there is a high frequency of Plasmid-mediated quinolone resistance genes in Escherichia coli isolates from clinical samples in South-Eastern Nigeria. These could be responsible for the high incidence of quinolone resistance reported in Enugu. There is a need for whole-genome sequencing to map out all resistance genes.

Factores asociados a la contaminación microbiológica de la carne de pollo comercializada en El Salvador / Factors associated with microbiological contamination of chicken meat marketed in El Salvador

Objetivo. Determinar los factores higiénico-sanitarios asociados a la contaminación microbiológica de la carne de pollo comercializada en los mercados municipales de El Salvador. Materiales y métodos. Se realizó un estudio transversal analítico en los 33 mercados municipales de las cabeceras departamentales de El Salvador. La muestra se calculó a partir de 456 puestos de venta, obteniendo un total de 256 puestos. Por cada puesto se obtuvo una muestra de carne de pollo. El análisis microbiológico se realizó en el Laboratorio Nacional de Salud Pública. Se calcularon frecuencias, porcentajes, medidas de tendencia central y de asociación utilizando SPSS versión 21. Resultados. En el 74% de las muestras se encontró Escherichia coli, en el 24%, Staphylococcus aureus y en el 16%, Salmonela spp. La presencia de Salmonella spp, estuvo asociada con el no uso de desinfectante para las manos y no utilizar toalla para secarse las manos. La presencia de E. coli estuvo asociada al uso de accesorios personales y la inadecuada temperatura de almacenamiento. Mientras que la presencia de S. aureus, estuvo asociada a la falta de lavado de manos, no utilizar toalla para secarse las manos y no utilizar delantal. Conclusión. Las condiciones higiénico-sanitarias de los manipuladores y de los puestos de venta están asociadas a la contaminación microbiológica en la carne de pollo comercializada en El Salvador.

Objective. To determine the hygienic-sanitary factors associated with the microbiological contamination of chicken meat sold at the municipal markets of El Salvador. Materials and methods. An analytical cross-sectional study was conducted in 33 municipal markets of the 14 departmental capitals of El Salvador. The sample consisted of 256 out of 456 possible market stalls. A sample of chicken meat was obtained from each market stall. The microbiological analysis was conducted at the National Public Health Laboratory. Frequencies, percentages, measures of central tendency and association were calculated with SPSS version 21. Results. Escherichia coli was found in 74% of the samples, Staphylococcus aureus in 24% and Salmonella spp. in 1%. The presence of Salmonella spp. was associated with not using hand sanitizer and not using towels for drying the hands. S. aureus was associated with the use of personal accessories and improper storage. The presence of S. aureus was associated with the lack of hand washing, not using a towel to dry the hands and not wearing an apron. Conclusion. The hygienic-sanitary conditions of the handlers and the market stalls were associated with microbiological contamination of chicken meat marketed in El Salvador.

Avaliação parasitológica e microbiológica de areia de praias de São Luís, Maranhão, Brasil / Parasitological and microbiological evaluation of sand from beaches in São Luís, Maranhão, Brazil

O Brasil é um país que possui um litoral onde se deparam grandes cidades e com grande fluxo de atividades humanas, o que pode levar a contaminação por microrganismos e parasitos. Diante desse contexto, o objetivo desse trabalho foi avaliar a ocorrência parasitária e microbiológica em areia de praias de São Luís, Maranhão. Para tal, foram coletadas quatro amostras de três praias, totalizando assim 12 amostras, cada área foi dividida em quatro faixas distintas, sendo duas secas e duas úmidas, e para cada amostra foram introduzidos coletores estéreis na areia com profundidade de 20 centímetros. As amostras foram identificadas e colocadas em caixa de isopor e foram conduzidas ao laboratório para análises, a parasitológica foi através do método de sedimentação espontânea e centrifugação e para a microbiológica utilizou-se o kit COLItest® para determinação de coliformes totais e termotolerantes (Escherichia coli). As areias, 100% (12/12) encontravam-se positivas para helmintos e/ou protozoários, sendo que o helminto e protozoário de maior ocorrência foram: 100% (12/12) Trichuris trichiura e 83,3% (10/12) Giardia lamblia, respectivamente. As análises microbiológicas, apresentaram 66,6% (8/12) com contaminação por coliformes totais, e 58,3% (7/12) para Escherichia coli, o ponto de coleta 3 da areia seca da praia de São Marcos (Sm3S) apresentou a maior contaminação por Escherichia coli (4,33x102 UFC/mL). As praias da orla marítima chamada Litorânea em São Luís estão contaminadas por parasitas como também por bactérias oriundas de fontes que entraram em contato com fezes seja de animais ou de humanos. Assim, aumenta-se a probabilidade de indivíduos que frequentem esses ambientes de adquirirem infecções.

Brazil has a coastline with large cities and a great flow of human activities, which can lead to contamination by microorganisms and parasites. Given this context, the objective of this study was to evaluate the parasitic and microbiological events in the sand of beaches in São Luís, Maranhão. Therefore, four samples were collected from three beaches, thus totaling 12 samples. Each area was divided into four distinct segments, two dry and two wet, and for each sample, sterile collectors were inserted into the sand at a depth of 20 centimeters. The samples were identified, placed in a Styrofoam box, and taken to the laboratory for analysis. The parasitological analysis was performed through spontaneous sedimentation and centrifugation, while the microbiological analysis used the COLItest® kit to determine total and thermotolerant coliforms (Escherichia coli). All the sand samples were positive (100%) for helminths and/or protozoa, and the most frequent helminth and protozoan were Trichuris trichiura (100%; n=12 ) and Giardia lamblia (83.3%; n=10), respectively. Microbiological analyses showed that 66.6% (8/12) were contaminated by total coliforms and 58.3% (7/12) by Escherichia coli. Collection point 3 of dry sand from São Marcos beach (Sm3S) showed the highest contamination by Escherichia coli (4.33x102 CFU/mL). The beaches on the seafront called Litorânea in São Luís are contaminated by parasites and fecal bacteria from animals or human sources on the beach. Thus, the probability of acquiring infections increases among individuals visiting these environments.

Monitoring fluoroquinolone resistance among ESBL-positive and ESBL-negative Escherichia coli strains isolated from urinary tract infections: An alert for empirical treatment

ABSTRACT Background: Bacterial resistance to extended-spectrum beta-lactamases (ESBL) is present worldwide. Empirical antibiotic therapy is often needed, and the use of fluoroquinolones, such as ciprofloxacin and norfloxacin, is common. This study aimed to analyze the urine cultures from 2,680 outpatients in January 2019, 2020, 2021, and 2022, with bacterial counts above 100,000 CFU/mL in which Escherichia coli was the etiological agent. Methods: We monitored the resistance of ESBL-positive and ESBL-negative strains to ciprofloxacin and norfloxacin and evaluated resistance rates. Results: Significantly higher fluoroquinolone resistance rates were observed among ESBL-positive strains in all years studied. Furthermore, a significant increase in the rate of fluoroquinolone resistance was observed between 2021 and 2022 in ESBL-positive and -negative strains, as well as from 2020 to 2021 among the ESBL-positive strains. Conclusions: The data obtained in the present study showed a tendency towards an increase in fluoroquinolone resistance among ESBL-positive and -negative E. coli strains isolated from urine cultures in Brazil. Since empirical antibiotic therapy with fluoroquinolones is commonly used to treat diverse types of infections, such as community-acquired urinary tract infections, this work highlights the need for continuous monitoring of fluoroquinolone resistance among E. coli strains circulating in the community, which can mitigate the frequency of therapeutic failures and development of widespread multidrug-resistant strains.

Colistin resistance in Escherichia coli and Klebsiella pneumoniae in humans and backyard animals in Ecuador / Resistencia a la colistina de las bacterias Escherichia coli y Klebsiella pneumoniae en humanos y animales de granja en Ecuador / Resistência à colistina em Escherichia coli e Klebsiella pneumoniae em humanos e animais de quintal no Equador

ABSTRACT Objective. Colistin is an antibiotic of last resort for treating serious Gram-negative bacterial infections. However, the misuse of colistin, especially as an animal growth promoter, has contributed to increasing antimicrobial resistance, mediated mainly through plasmid transfer of the mcr-1 gene. This study assessed the prevalence of phenotypic and molecular colistin resistance in Escherichia coli and Klebsiella pneumoniae in Ecuador in healthy humans and their chickens and pigs. Methods. Fecal samples were collected from humans and their chickens and pigs in two rural coastal and Amazon regions between April and August 2020. Gram-negative bacteria were isolated and identified using conventional techniques. Phenotypic resistance was determined using the broth microdilution technique, and the mcr-1 gene was detected using conventional polymerase chain reaction. Results. A total of 438 fecal samples were obtained from 137 humans, 147 pigs and 154 chickens. The prevalence of E. coli isolates was 86.3% (378/438) and K. pneumoniae, 37.4% (164/438). Overall, the mcr-1 gene was found in 90% (340/378) of E. coli isolates, with higher prevalences found in isolates from coastal regions (96.5%, 191/198), humans (95.6%, 111/116) and chickens (91.8%, 123/134); for K. pneumoniae, the gene was found in 19.5% (32/164) of isolates, with equal distribution between regions and hosts. Only four isolates, two E. coli and two K. pneumoniae, showed phenotypic resistance: mcr-1 was present in both E. coli strains but absent in the K. pneumoniae strains. Conclusions. Despite a low prevalence of phenotypic resistance to colistin, the high prevalence of the mcr-1 gene in E. coli is of concern. Ecuador's ban on using colistin in animal husbandry must be enforced, and continual monitoring of the situation should be implemented.

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RESUMO Objetivo. A colistina é um antibiótico de último recurso para o tratamento de infecções graves por bactérias Gram-negativas. Entretanto, o uso indevido da colistina, principalmente como promotor de crescimento animal, tem contribuído para o aumento da resistência a antimicrobianos, principalmente por transferência horizontal do gene mcr-1 mediada por plasmídeos. Este estudo avaliou a prevalência de resistência fenotípica e molecular à colistina em Escherichia coli e Klebsiella pneumoniae no Equador em humanos hígidos e em galinhas e porcos por eles criados. Métodos. Entre abril e agosto de 2020, foram coletadas amostras de fezes de habitantes de duas regiões litorâneas e amazônicas do Equador e de galinhas e porcos por eles criados. Bactérias Gram-negativas foram isoladas e identificadas por meio de técnicas convencionais. A resistência fenotípica foi determinada pela técnica de microdiluição em caldo, e o gene mcr-1 foi detectado por reação em cadeia da polimerase convencional. Resultados. Foram obtidas 438 amostras fecais de 137 humanos, 147 suínos e 154 galinhas. A prevalência de isolados de E. coli foi de 86,3% (378/438), e de K. pneumoniae, 37,4% (164/438). Em geral, o gene mcr-1 foi encontrado em 90% (340/378) dos isolados de E. coli, com maiores prevalências encontradas em isolados de regiões litorâneas (96,5%, 191/198), humanos (95,6%, 111/116) e galinhas (91,8%, 123/134); para K. pneumoniae, o gene foi encontrado em 19,5% (32/164) dos isolados, com igual distribuição entre regiões e hospedeiros. Somente quatro isolados, dois de E. coli e dois de K. pneumoniae, demonstraram resistência fenotípica: o gene mcr-1 estava presente em ambas as cepas de E. coli, mas ausente nas de K. pneumoniae. Conclusões. Apesar da baixa prevalência de resistência fenotípica à colistina, a alta prevalência do gene mcr-1 em E. coli é preocupante. É preciso fiscalizar a proibição ao uso agropecuário de colistina no Equador e implementar o monitoramento contínuo da situação.

Metabolic engineering of Escherichia coli for adipic acid production / 生物工程学报

Adipic acid is a high-value-added dicarboxylic acid which is primarily used in the production of nylon-66 for manufacturing polyurethane foam and polyester resins. At present, the biosynthesis of adipic acid is hampered by its low production efficiency. By introducing the key enzymes of adipic acid reverse degradation pathway into a succinic acid overproducing strain Escherichia coli FMME N-2, an engineered E. coli JL00 capable of producing 0.34 g/L adipic acid was constructed. Subsequently, the expression level of the rate-limiting enzyme was optimized and the adipic acid titer in shake-flask fermentation increased to 0.87 g/L. Moreover, the supply of precursors was balanced by a combinatorial strategy consisting of deletion of sucD, over-expression of acs, and mutation of lpd, and the adipic acid titer of the resulting E. coli JL12 increased to 1.51 g/L. Finally, the fermentation process was optimized in a 5 L fermenter. After 72 h fed-batch fermentation, adipic acid titer reached 22.3 g/L with a yield of 0.25 g/g and a productivity of 0.31 g/(L·h). This work may serve as a technical reference for the biosynthesis of various dicarboxylic acids.

Modular engineering of Escherichia coli for high-level production of l-tryptophan / 生物工程学报

As an essential amino acid, l-tryptophan is widely used in food, feed and medicine sectors. Nowadays, microbial l-tryptophan production suffers from low productivity and yield. Here we construct a chassis E. coli TRP3 producing 11.80 g/L l-tryptophan, which was generated by knocking out the l-tryptophan operon repressor protein (trpR) and the l-tryptophan attenuator (trpL), and introducing the feedback-resistant mutant aroGfbr. On this basis, the l-tryptophan biosynthesis pathway was divided into three modules, including the central metabolic pathway module, the shikimic acid pathway to chorismate module and the chorismate to tryptophan module. Then we used promoter engineering approach to balance the three modules and obtained an engineered E. coli TRP9. After fed-batch cultures in a 5 L fermentor, tryptophan titer reached to 36.08 g/L, with a yield of 18.55%, which reached 81.7% of the maximum theoretical yield. The tryptophan producing strain with high yield laid a good foundation for large-scale production of tryptophan.

Effect and mechanism of cytochrome P450 1A1 on regulating phagocytosis of macrophage / 中华危重病急救医学

Objective:To explore the effect and mechanism of cytochrome P450 1A1 (CYP1A1) on regulating phagocytosis of macrophage treated with Escherichia coli ( E.coli). Methods:① The mouse leukemia cells lines of monocyte macrophage RAW264.7 (RAW) were cultured in vitro and treated with 30 multiplicity of infection (MOI) dosages of E.coli for 40 minutes, glycerin control group was set up to observe the change of CYP1A1 during infection. ② The RAW cells with CYP1A1 overexpression (CYP1A1/RAW) and knock out (CYP1A1 KO/RAW) were cultured in vitro and treated with 30 MOI E. coli for 40 minutes, while the negative controlled RAW cells (NC/RAW) were established as control to observe the relationship between cell phagocytosis and CYP1A1 expression, and the effect of CYP1A1 on phagocytic receptor [scavenger receptor-A (SR-A)] and its signal pathway [mitogen-activated protein kinase (MAPK) pathway]. ③ NC/RAW and CYP1A1 KO/RAW cells were cultured in vitro and pretreated with 1 μmol/L extracellular signal-regulated kinase (ERK) inhibitor (U0126) for 2 hours, and then treated with 30 MOI E.coli for 40 minutes, phosphate buffered solution (PBS) control group was set up to observe whether the effect of CYP1A1 on phagocytosis through controlled the MAPK pathway. ④ The RAW cells were cultured in vitro and pretreated with 100 nmol/L CYP1A1 hydroxylase active product 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] for 2 hours, and then treated with 30 MOI E.coli for 40 minutes, and PBS control group was set up to observe whether the effect of CYP1A1 on phagocytosis was related to CYP1A1 hydroxylating metabolite. ⑤ The RAW cells with overexpression CYP1A1 hydroxylase-activity mutation (CYP1A1m/RAW) were cultured in vitro and treated with 30 MOI E.coli for 40 minutes, the CYP1A1/RAW cells were set up as control group to observe whether the effect of CYP1A1 on phagocytosis was related to CYP1A1 hydroxylase-activity. Results:① Compared with glycerin control group, CYP1A1 mRNA expression was significantly increased by E.coli stimulation (2 -ΔΔCt: 7.79±0.71 vs. 1.00±0.00, P < 0.05), indicating that CYP1A1 might participate in regulating infection progress. ② Compared with NC/RAW cells, the number of E.coli colonies phagocytized by CYP1A1/RAW cells was significantly decreased after 40 minutes of E.coli stimulation (×10 3 CFU/mL: 4.67±3.06 vs. 15.67±5.03, P < 0.05), while CYP1A1 KO/RAW cells had a significant increase in the number of E.coli colonies phagocytized (×10 3 CFU/mL: 46.00±5.29 vs. 15.67±5.03, P < 0.05), suggesting that CYP1A1 might negatively control macrophage phagocytosis function. Meanwhile, compared with NC/RAW cells, the expression of SR-A mRNA in CYP1A1/RAW cells was significantly down-regulated (2 -ΔΔCt: 0.31±0.03 vs. 1.00±0.00, P < 0.05), and the activation level of ERK was significantly reduced. However, the expression of SR-A mRNA in CYP1A1 KO/RAW cells was significantly up-regulated (2 -ΔΔCt: 3.74±0.25 vs. 1.00±0.00, P < 0.05), and the activation of ERK was enhanced, indicating that CYP1A1 could negatively regulate phagocytic receptors and their signaling pathways.③ Compared with PBS, U0126 pretreatment significantly inhibited the CYP1A1 knockout induced upregulation of SR-A mRNA expression (2 -ΔΔCt: 0.62±0.05 vs. 4.38±0.39, P < 0.05) and ERK activation, and inhibited the enhancement of phagocytosis in macrophages induced by CYP1A1 knock out [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 12.67±1.15 vs. 45.33±4.16, P < 0.05], suggesting that CYP1A1 inhibited macrophage phagocytosis function by regulating ERK activation. ④ Compared with PBS, the phagocytosis of RAW cells pretreated with 12(S)-HETE did not change significantly [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 17.00±1.00 vs. 16.33±2.52, P > 0.05], suggesting that CYP1A1 might not control phagocytosis function by its hydroxylase-activity metabolism 12(S)-HETE. ⑤ Compared with CYP1A1/RAW cells, there was no significant change in the phagocytic function of CYP1A1m/RAW cells [ E.coli colonies phagocytized by cells (×10 3 CFU/mL): 3.67±1.15 vs. 3.33±0.58, P > 0.05], suggesting that CYP1A1 might not control phagocytosis function by its hydroxylase-activity. Conclusion:CYP1A1 can negatively regulate the phagocytosis of macrophages by inhibiting the activation of ERK and reducing the expression of SR-A, but this regulatory effect is not related to the activity of CYP1A1 hydroxylase and its pro-inflammatory metabolism 12(S)-HETE.

Biological characteristics of Escherichia coli phage and Staphylococcus aureus phage isolated from sewage / 西安交通大学学报(医学版)

【Objective】 Escherichia coli phage (ECP) and Staphylococcus aureus phage (SAP) isolated from sewage were used as research objects, and their biological characteristics were analyzed to provide new experimental materials for the application of phages. 【Methods】 ECP and SAP were purified and cultured by double-layer agar method. Then a series of biological characteristics of these two phages were preliminarily analyzed by electron microscope observation, optimal multiplicity of infection (MOI) test, one-step growth curve test, temperature, pH, chloroform and ultraviolet sensitivity tests, respectively. 【Results】 The results of biological characteristics showed that ECP and SAP were both virulent phages, belonging to myoviridac family. Their optimal MOI was 10-1, and they had strong resistance to ultraviolet light. The cleavage volume of ECP was 76.3 PFU/cell, while that of SAP was 8.3 PFU/cell. ECP had a wide range of temperature tolerance and could stably survive at 30-50 ℃, while SAP was more sensitive to temperature and could be completely inactivated at 50 ℃ for 1 h. ECP could maintain a good lysis activity in the range of pH 5-11, while SAP in the range of pH 6-9. ECP had strong resistance to chloroform and was non-membranous phage, while SAP was more sensitive to chloroform and was a membranous phage. 【Conclusion】 ECP and SAP are both virulent phages and have strong resistance to ultraviolet light. The lysability, temperature, pH, and chloroform tolerance of ECP are stronger than those of SAP.